At the highest level, that would be when one nation wins all the medals in the Summer Olympics Athletics.
After the 1908 Olympics, a sweep became an increasingly treasured status symbol of national dominance in an event.
Sweeps have happened in every long term event in the individual program, except the 5000 metres.
Ellery Clark, Robert Garrett and James Connolly swept two events together in 1896.
More recently, Carl Lewis has led three Olympic sweeps, Mike Powell has finished behind him in two.